Mining tool



A. L. MCDONALD.

MINING TOOL.

APPLICATION FILED NOV. I1, 1920.

1 327,609, I Patented Aug. 29, 1922.

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UNITED MINING rooL.

Application filed November 11, 1820.

To all whom it may concern:

Be it known that I, Annnncr L. MoDrmmnn,

a citizen of the United States, residing at lVoodlawn, in the county of Allegheny and State of Pennsylvania, have lnvented certain new and useful Improvements in Mining Tools, of which the following is a specification.

My invention consists of an improvement in mining tools, and particularly relates to a reamer for enlarging the inner end of a blasting hole.

In blasting coal or other minerals, a great advantage over the ordinary practice of exploding the charge in the end of a bore hole is secured by enlarging the inner end. This is especially true when the boreis enlarged by a lateral cavity extending all around the central bore and with a flat front wall on a plane at right angles to the axial center of the bore. When so made, the explosive charge of powder, or the like, being confined between the rear end front walls of the enlarged cavity, surrounding the central bore hole, will act with very great force against the front wall particularly, and will break the coal, etc. outwardly and laterally on diverging lines.

By such practice, the usual undercutting of a vein is avoided, and blasting may be successfully and cheaply done by charges exploded in the rear of the middle part of the breast of the vein.

In carrying out my invention, I have produced a tool consisting of a cylindrical barrel capable of fitting somewhat loosely in a cylindrical bore hole having at its inner end an eccentrically mounted laterally ex tensible cutting tool capable of being gradually adjusted in and rotated by the barrel to cut an enlarged cavity at the inner end of the bore hole having fiat front and rear walls and of an area several times the cross sectional area of the bore hole, as hereinafter described.

Referring to the drawings, showing one preferred form of the invention,

Fig. 1 is a View in side elevation, showing the tool in position at the termination of the cut;

Fig. 2 is an enlarged view'of the outer or handle end of the tool;

Fig. 3 is a longitudinal section, partly broken away, on the line III-III of Fig. 2;

Figs. 4, 5 and 6 are views of the inner end Letters Pa tented Aug. 29,

Serial. No. 423,240.

of the tool showing successive positions of the cutter.

In the drawings, 2 is a cylindrical barrel of pipe form, of a length sufficient to extend inwardly of the length ofanordinary bore hole 3, with sufficient extension in front of itfor easy manipulation, in Fig. 1. At each end are bearing heads 4- and- 5 respectively, fixedly securedto the barrel 2 by any suitable means, welding or riveting. Inner head 5 is preferably provided with a clearance opening 7 for passage of cuttings outwardly and into the. barrel.

At one side of the axial center, eccentric thereto, and as close to the wall of the barrel at one side as is practicable, is a cutter shaft 8 journalled in bearings 9 and 10 of heads and 5, and provided atits inner end with the cutter arm 11 having the cutting terminal as shown. Arm 11 is secured by its hub to the squared or otherwise formed inner terminal 12 of shaft 8 and held thereon by a retaining nut 13 or the like. At its other end, shaft 8 is provided with a squared or otherwise formed terminal 14 so that it may be engaged by a wrench or other tool and adjusted to the cutter 11 gradually outa spring-pressed pawl 16 mounted on head 4t. so that the shaft maybe gradually adjusted during the cutting operation and held in extended position. It may also be reversed to withdraw the cutter inwardly, as in Fig. a, by retracting the pawl, or merely turned clear around to the position of l g. 4. When it has been withdrawn and is'in nor mal or retracted position, the cutter extends diametrically across the pipe, so that it may have a maximum length for a a barrel of given diameter.

The outer end of the barrel 2 is provided with a turning crank handle 17 secured in any convenient way, as by a ring 18 embracing the end of the barrel and secured thereon, by a set screw 19 or otherwise.

The operation is as follows:

The hole 3'having been bored to the desired depth, the barrel 2 is inserted with the cutter l1 retracted, as in Fig. 4. Shaft 8 is then turned by its terminal 14:, say one tooth of ratchet wheel 15, which brings the terminal of the cutter against the inner peripheral portion of the bore hole with sufiicient pressure. The entire barrel and cutter are then rotated by cranlr handle l7, the barrel being loosely journalled in the bore hole, until the cutter has made its initial cut, and shaft 8 is then again adjusted for say one tooth of the ratchet w i el and the barrel again turned as before.

This operation is continued, the cutter operating 011 an enlarging peripheral path as indicated at a, Z), and finally resulting in the cavity 0, Fig. l, with the cutter extended to its limit. Pawl 16 may be then retracted and shaft 8 reversed, or may be more easily continuously turned in the same direction,v

to close in the cutter, when the entire tool may be withcrawn, have passed through opening 7 and remain in the barrel may be easily discharged by dumping vertically through opening 7, as will be readily understood.

The cavity may then be filled with the explosive charge. either fully or partially,

and nroperl tam'eed and fired. The front l. l A

wall (Z being towards the direction of least resistance will receive substantially the full effect of the blast, its area being very largely greater than that of the central yore iole 3 with the result that the shot will force the mass of mineral in front of wall cl outwardly on the diverging lines of a conic section.

If it is desired to increase the depth of tl? cylindrical cavity 0 after the same is cut,tl original cutter may be removed another substituted of wider cutting face, Within any particular limits.

"The tool is comparatively simple in construction, and is very durable and eiiicient in operation, and not liable to get out of order. It may be changed or varied in dif ferent details or otherwise by the skilled mechanic to suit various conditions of use,

but all such changes are to be considered as within the scope of the following claims.

WVhat I claim is:

1. A mining tool consisting of a hollow cylindrical rotatable barrel provided with aneccentrically mounted laterally extensible cutter on one end thereof.

2. A mining tool consisting of a hollow cylindrical rotatable barrel provided with an eccentrica'lly mounted laterally extensible Any cuttings which.

' signature.

cutter normally extending across the inner thereof, means for adjusting the cutter, and means for rotating the barrel.

8. A mining tool consisting of a cylindrical. body portion having an eccentrically located cutter shaft provided at its inner end with laterally adjustable cutter normally extending across the inner end of the barrel and an outer adjusting terminal, means for holding the cutter shaft and cutter in adjusted position, and means for rotating the vindrical body portion.

in a mi ng tool. the combination of a tubular body portion having ecccntrically located bearings at each end, a cutter shaft extending therethrough, a laterally swinging cutter securedto the projecting inner end of said shaft outside of the barrel. and across one end thereof, an adjusting terminal and ratchet mechanism at the outer end said shaft, and a crank handle secured to the outer end of the tubular body'portion.

5. A mining tool comprising a barrel provided with an eccentrically mounted laterally movable cutter, arranged to normally extenddiametrically across the barrel.

6. A mining tool comprising a barrel provided with an eccentrically. mounted movable cutter, arranged to be rotated rele nding across the end of the barrel with its center of rotation and cutting portion substantially diametrically opposed, so that the cutter may be of maximum length.

7. A mining tool comprising ahollow cylindrical rotatable-barrel, an apertured bean ing member at one end of the barrel having an eccentric bearing therein, a bearing mem her at the other end of said barrel, ashaft carried in said. bearing members and having its inner end. projecting beyond the inner end of said barrel, a cutter on said shaft, means for turning the barrel, means for turning the cutter to project it laterally, the opening in said apertured hearing member being de signed to provide for the passage'of cuttings into the barrel.

In test mony whereof I hereunto afliX my ALBERT L. MCDONALD. 

